Mesoporous Ta2O5 nanoparticles (NPs) with high surface area were prepared using an 1-methyl 3-(2-bromoethyl) imidazolium bromide ionic liquid (IL) as structure directing and porous inducing agent. We have characterized the Ta2O5 nanoparticles (NPs) by XRD, BET analysis, TEM, SEM, DRS, FTIR, Raman spectroscopy and TG-DTA. From BET analysis a large surface area of asprepared Ta2O5 NPs was found to be 236.1 m(2) g(-1). More importantly, Ta2O5 nanoparticles are less explored anode material for lithium ion battery as well as an effective photocatalyst for hydrogen generation. The significant reversible capacity of 150 mAh g(-1) has been observed in Ta2O5 NPs even after 50 cycles at C/10 current rate. In addition to this, asprepared Ta2O5 NPs synthesized using IL exhibited remarkable hydrogen generation of 563.5 mu molg(-1) h(-1) compared to other Ta2O5 samples which are due to high surface area, small pore wall thickness and presence of surface hydroxyl groups on the photocatalyst. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.